Fen Bi̇li̇mleri̇ Dergi̇si̇

Marmara Üniversitesi fen bilimleri dergisi, 2013

Organic and inorganic pollutants found in municipal landfill leachate lead to severe problems for the environment when directly discharged to water bodies without treatment. Due to the existence of recalcitrant organics in leachate, advanced oxidation processes (AOP) are mostly applied to biologically treated leachate as a polishing step. In this study, the effectiveness of Fenton process on leachate treatment was examined. The Fenton process was applied to both young (untreated) and biologically treated leachate provided from Şile Kömürcüoda Landfill in Istanbul. It was treated by using up flow anaerobic sludge blanket (UASB) reactor and membrane bio-reactor (MBR) processes respectively prior to AOP application. In addition, the combination of Ultraviolet (UV)/Fenton and Ultrasound (US)/Fenton processes were applied to biologically treated leachate to improve the efficiency of Fenton process. The results suggested that, Fenton process is an efficient oxidation method for the treatment of organic matter and color in leachate. It was able to remove 70 % chemical oxygen demand (COD) from the raw leachate, while for biologically treated leachate the COD removal was over 50 %. On the other hand, color removal was observed to be 90 % and 98% in old and young leachate respectively. It was also seen that the additional treatment techniques used in the study did not improve the treatment efficiency of Fenton process.

Water and Environment Journal, 2012

The Fenton process was used with the objective of improving the biodegradability of the leachate pretreated biologically up to a value compatible with a subsequent biological treatment. The optimum reaction and settlement pH was 3, both for the organic matter removal and for the improvement of the biodegradability. The chemical oxygen demand (COD) removal increased at increasing Fe 2+ dosages, from 75.6% for 300 mg/L to 89.0% for 1400 mg/L. The most significant enhancement (84.8%) was obtained with 800 mg Fe 2+ /L. However, the biological oxygen demand/chemical oxygen demand ratio (BOD/COD) was almost the same at all the Fe 2+ dosages, around 0.29. Moreover, varying the H 2 O 2 concentration between 600 and 3600 mg/L, COD removal percentages were between 85.

Iranian Journal of Environmental Health Science & Engineering, 2012

Advanced oxidation processes like Fenton and photo-Fenton have been effectively applied to oxidize the persistent organic compounds in solid waste leachate and convert them to unharmful materials and products. However, there are limited data about application of Fenton-like process in leachate treatment. Therefore, this study was designed with the objective of treating municipal landfill leachate by Fenton, Fenton-like and photo-Fenton processes to determine the effect of different variables, by setting up a pilot system. The used leachate was collected from a municipal unsanitary landfill in Qaem-Shahr in the north of Iran. Fenton and Fenton-like processes were conducted by Jar-test method. Photo-Fenton process was performed in a glass photo-reactor. In all processes, H2O2 was used as the oxidant. FeSO4.7H2O and FeCl3.6H2O were used as reagents. All parameters were measured based on standard methods. The results showed that the optimum concentration of H2O2 was equal to 5 g/L for the Fenton-like process and 3 g/L for the Fenton and photo-Fenton processes. The optimum ratio of H2O2: Fe+2/Fe+3 were equal to 8:1 in all processes. At optimum conditions, the amount of COD removal was 69.6%, 65.9% and 83.2% in Fenton, Fenton-like and photo-Fenton processes, respectively. In addition, optimum pH were 3, 5 and 3 and the optimum contact time were 150, 90 and 120 minutes, for Fenton, Fenton-like and photo-Fenton processes, respectively. After all processes, the biodegradability (BOD5/COD ratio) of the treated leachate was increased compared to that of the raw leachate and the highest increase in BOD5/COD ratio was observed in the photo-Fenton process. The efficiency of the Fenton-like process was overally less than Fenton and photo-Fenton processes, meanwhile the Fenton-like process was at higher pH and did not show problems.

CLEAN – Soil, Air, Water, 2013

The treatment of landfill leachate with physico‐chemical and Fenton and Fenton‐like processes was investigated. Additionally, the acute toxicities of the raw, the physico‐chemical pre‐treated, and the Fenton and Fenton‐like oxidation treated leachates on activated sludge microorganisms are given (determined by the ISO 8192 (respiration inhibition test)). Pre‐treatment with lime positively affected the biodegradability of the sludge by preventing inhibition. The Fenton and Fenton‐like processes resulted in high chemical oxidation demand (COD) (>80%) removal performance from leachate samples. The inhibitory effects of the Fenton and Fenton‐like reagents on activated sludge mixtures decreased. In addition to toxicity, the COD removal efficiencies and the operation costs of the applied processes were determined.

IRANIAN JOURNAL OF …, 2009

Backgrounds and Objectives: Leachate is one of the landfill products and also a wastewaterbearing the most advers effects on the environment. Biological methods are usually employed fortreatment of young leachate (1-2 years) wich is of high concentration of organic compounds withlow ...

In recent years, studies of leachate treatment by conventional Fenton, photo-Fenton and electro-Fenton processes have indicated that these methods can effectively reduce concentrations of organic contaminants and color. In addition, the process can increase the biodegradable fraction of organic constituents in leachate, particularly in mature or biologically recalcitrant leachate. Oxidation and coagulation both play important roles in the removal of organics. Initial pH, dosages of Fenton reagents, aeration, final pH, reagent addition mode, temperature, and UV irradiation may influence final treatment efficiency. In this paper, current knowledge of performance and economics of Fenton processes for treatment of landfill leachate as reported for laboratory, pilot and full-scale studies is reviewed, with the conclusion that the Fenton process is an important and competitive technology for the treatment or pretreatment of landfill leachate.

ampublisher.com

Abstract—This research was undertaken to investigate various operating conditions of Fenton treatment process for minimizing the sludge production and maximizing COD as well as colour removal from landfill leachate. Sample was collected from Matuail landfill site, ...

Journal of Hazardous Materials, 2005

The treatment of landfill leachate by Fenton process was carried out in a batch reactor. The effect of operating conditions such as reaction time, pH, H 2 O 2 to Fe(II) molar ratio, Fenton's reagent dosage, initial COD strength, feeding mode, the type of polymer, and temperature on the efficacy of Fenton process was investigated. It is demonstrated that Fenton's reagent can effectively degrade leachate organics. Fenton process was so fast that it was complete in 30 min. The oxidation of organic materials in the leachate was pH dependent and the optimal pH was 2.5. The favorable H 2 O 2 to Fe(II) molar ratio was 1.5, and organic removal increased as dosage increased at the favorable H 2 O 2 to Fe(II) molar ratio. The efficacy of Fenton process was improved by adding Fenton's reagent in multiple steps than that in a single step. Furthermore, the stepwise addition of both hydrogen peroxide and ferrous iron was more effective than that of hydrogen peroxide only. Sludge settling characteristics were much improved with the addition of the proper polymer. Temperature gave a positive effect on organic removal.

Land filling is one of the least expensive methods for disposal of municipal solid waste (MSW). Hence about 90% of MSW is disposed in the open dumps and landfill unscientifically, creating problem to public health and the environment. The leachate generated from the municipal landfill contains organic and inorganic pollutants, which make it unsuitable for discharge in natural bodies without any prior treatment. Advanced oxidation process (AOPs) are promising methods to treat effectively the recalcitrant substances present in landfill leachate. Among APOs fenton process is considered the most promising treatment for remediation of highly contaminated water. In this study electro fenton pretreated landfill leachate was treated by membrane bioreactor process and then post treated by electro fenton process. The pretreated values of parameters were taken from previous studies which has BOD/COD ratio 0.39. Membrane bioreactors have proven quite effective in removing organic and inorganic contaminants as well as biological entities from waste water. In MBR the membrane arrangement consist of hollow fiber membrane module having pore size of 0.1µm. After MBR process, the effluent quality did not meet the general Standards for discharge of environmental pollutants. But after post treatment all the parameters have met the relevant Indian standards for discharge as irrigation water and all the parameter except BOD and sulphide have met the relevant Indian standards for discharge in to inland surface water.

Archives of Environmental Protection, 2013

Treatment of leachate from an exploited since 2004 landfi ll by using two methods of advanced oxidation processes was performed. Fenton's reagent with two different doses of hydrogen peroxide and iron and UV/H 2 O 2 process was applied. The removal effi ciency of biochemically oxidizable organic compounds (BOD 5), chemically oxidizable compounds using potassium dichromate (COD Cr) and nutrient (nitrogen and phosphorus) was examined. Studies have shown that the greatest degree of organic compounds removal expressed as a BOD 5 index and COD Cr index were obtained when Fenton's reagent with greater dose of hydrogen peroxide was used-effi ciency was respectively 72.0% and 69.8%. Moreover, in this case there was observed an increase in the value of ratio of BOD 5 /COD Cr in treated leachate in comparison with raw leachate. Application of Fenton's reagent for leachate treatment also allowed for more effective removal of nutrients in comparison with the UV/H 2 O 2 process.